Vehicles which have camera-based driver assistance systems are known. Such vehicles have at least one camera system having at least one camera which records images with reproductions of a detection area, preferably a detection area in the direction of travel in front of the vehicle, and generates image data corresponding to the images. The generated image data are then processed with the aid of suitable processing routines. For processing the image data preferably digital signal processors are used in the vehicle. In this connection, it is known to detect various objects in individual images and to compare the position of an object in various images to one another. In particular, the objects are tracked over several images. For this purpose, in particular so-called tracking methods are used.
In addition to so-called lane keeping assistants, a camera-based monitoring of the dead angle and a camera-based traffic sign recognition, also camera-based driver assistance systems for controlling the light output of the head lights of vehicles are known. It is the object of these camera-based assistance systems for the control of the light output of the headlights of the vehicle to achieve a maximized illumination of the area in front of the vehicle, without shining towards and hence hindering other road users, in particular road users in cars driving ahead or in oncoming cars. To this end, the driver assistance system evaluates further vehicle data such as the speed of the vehicle and the steer angle of the vehicle in addition to the determined image data. The driver assistance system preferably receives this further information with the aid of data transferred via a vehicle bus of the vehicle.
A change in the pitch angle of the vehicle results in that the angle of the light emitted by the headlights of the vehicle with respect to the horizontal likewise changes. A permanent change in the pitch angle, for example by an increase in the load in the rear or in the front area of the vehicle can be compensated for by known headlight range regulation systems. The abrupt change in the pitch angle in the dynamic and high dynamic range, in particular as a result of an unevenness of the road surface and the speed at which the vehicle drives on the road, results in that the area in front of the vehicle is not optimally illuminated, i.e. not in a maximized way and/or that other road users are affected by the light emitted by the headlights.
A conceivable solution is to reduce the light output of the headlights so far that given changes in the pitch angle of the vehicle within the usual range other road users are not impaired. However, this defensive control strategy of the headlights has the disadvantage that then the area in front of the vehicle is not illuminated in a maximized way.
The cameras of camera systems of the driver assistance systems integrated in known vehicles have, at least during the travel of the vehicle, a position that is known and can be assumed as being constant relative to the vehicle and hence relative to the vehicle coordinate system so that given a change in the pitch angle of the vehicle a change in the pitch angle of the camera likewise occurs.
From the document EP 1 437 259 A1, a device and a method for setting the pitch of a vehicle headlight are known, in which a specific point of light is generated and detected. Dependent on the determined position of the point of light, a setting of the pitch of the headlight is performed.
From the document DE 10 2007 041 781 A1, a device and a method for recognizing vehicles by the identification of points of light in recorded images are known. Here, it is verified whether a point of light originates from a vehicle or not.
From the document EP 642950 B1, an automatic headlight adjustment control is known, in which based on the detection of the own light distribution a headlight range regulation is performed.